Sound generator



July 16, 1963 J. c. HOPKINS ETAL SOUND GENERATOR 2 Sheets-Sheet 1 Filed April 25, 1946 INVENTORS FIG.

C HOPKINS G BENNETT JAMES OWEN ATTORNEY July 16, 1963 J. c. HOPKINS ETAL I 3,097,600

SOUND GENERATOR Filed April 25, 1946' 2 Sheets- Sheet 2 Q" ,..50 INVENTORS JAMES c. HOPKI i OWEN c. BENNE FIG. 6. BY

ATTORNEY 3,097,600 SOUND GENERATOR James C. Hopkins, Cambridge, Mass, and Owen G. Bennett, Baltimore, Md., assignors to the United States of America as represented by the Secretary of the Navy Filed Apr. 25, 1946, Ser. No. 664,870 7 Claims. (Cl. 102-7) (Granted under Title 35, US. Code (1952), sec. 266) This invention relates to a sound generator and is illustrated herein as embodied in an explosive, underwater, noise-making device for masking the sound of a sub marine during the performance of evasion maneuvers.

It is an object of the invention to provide an explosive noisemaker adapted to be ejected from a signal tube of a submenged submarine and to fire a rapid succession of explosive charges underwater.

A further object of the invention lies in the provision of a gasket means for effecting a waterseal for the noisemaker.

With the above and other objects and features in view, the invention will now be described with reference to the accompanying drawings which illustrate a preferred embodiment of the invention and will be pointed out in the claims.

In the drawings:

FIG. 1 is a cross sectional view of the explosive noisemaker;

FIG. 2 is a front elevation thereof;

FIG. 3 illustrates the noisemaker with a parachute suspension;

FIG. 4 is a cross sectional view taken along the line IVIV of FIG. 1;

FIG. 5 is a detailed cross sectional elevation showing the trigger mechanism in fired position; and

FIG. 6 is a partial cross sectional view through one of the explosive holding discs showing the interconnecting opening at the top of the fuse groove.

With reference to FIGS. 1 and 3, the device generally indicated at 10, consists of a series of discs 12 stacked on a hollow metal rod 14 threaded at its opposite ends. The rod 14 is screwed at one end into a base assembly 16 comprising a trigger mechanism and a time delay fuse later to be described. The opposite end of rod 14 is held by a nut 18 and a top plate 28. A recess 22 in plate 20 surrounds the rod 14, a steel washer 24 and a rubber grommet 26 being positioned in the recess.

The base assembly 16 (FIG. 1) includes a circular base 28 to which is secured a trigger mechanism.

The discs 12 (FIGS. 1 and 6) are each provided at their upper surface with a shallow, inner, annular recess 38. A gasket 42 is positioned over each recess 38 and a relatively thin transfer plate 46 is interposed between the base 28 and the lowermost disc 12 of the stack. It is apparent that by taking up on the nut 18, the stack of discs 12 and the interposed gaskets 42 are compressed tightly together between the top plate 20 and base 28, the lapping of gaskets 42 over the peripheries of the recesses 38 insuring a water-tight seal of the parts. Furthermore, the washer 24 will tend to compress the rubber grommet 26 against the threads of rod 14 thus providing a water-tight joint between the top plate 20 and rod 14. By the foregoing, it is seen that a water-tight seal is effected over each explosive cap 50 and throughout the entire assembly. Preferably, the entire assembly is dipped for multiple coatings in a varnish of the Bakelite type. This is done, following a baking of the unit in an oven at a temperature approximately 100 F. to expand and expel as much imprisoned air as possible and to cause a reduction of internal air pressure as the warm unit is dipped in the cooler varnish. The water seal effected by the foregoing pro- 3,897,688 Patented July 16, 1963 cedures has been found in practice to withstand as much or more than 600 psi. hydraulic pressure as well as the terrific shock pressures developed during the series of under-water explosions.

Each disc 12 (FIGS. 1, 4 and 6) has a series of openings 48 in the outside wall which openings are adapted to house explosive caps '50. Small holes 52 connect each opening 48 with a circular groove 54 of rectangular cross sectional shape. A delay fuse 56 is packed in each groove 54 and relay fuses 58 are packed in the small holes 52. A single aperture or orifice 60 is provided in the top of each groove 54 thereby permitting the fuse train to communicate with the groove 54 of the next adjacent disc. Similarly, a single orifice 61 is provided in the transfer plate 46, the position of this orifice determining the delay from the initial firing to the firing of the first explosive cap 50. It is apparent that by the rod-nut adjustment 14--18 the apertures 60 may be aligned or staggered in the assembly with respect to each other, staggered formation being variable up to a limit of 180 degrees one from the other.

The trigger mechanism, as stated above, is carried by the base 2-8-32 (FIGS. 1 and 5) which is secured by screws such as 62 to the disc 28. A tripping lever 64 having a key projecting portion 65 is pivoted at 66 to an upstanding lug 68 fixed to the base 32. A hammer 70 is also pivoted as at 72 to the lug 68 and a spring 74 tends to pivot the hammer 70 towards the base 3-2. In assembly, the trigger mechanism is cooked and then locked in position by a safety ring pin 76 and stub shaft 78. As best shown in FIG. 1, the stub shaft 78 passes through an opening 80 in the lever 64 and through openings 82 (FIG. 5) in guide lugs 84. The pin 76 passes through an opening 86 in the shaft 78 and projects into a hole 88 in the disc 28 to lock the shaft 78 in position, thus preventing any movement of lever 64.

An initial primer 90 (FIGS. 1 and 5) is held in a metal holder 92 which projects inside the hollow rod 14. A passageway 93 extends entirely through the center axis of the holder 92 and communicates with a relay fuse 94 that is packed in the hollow rod 14. The relay fuse 94 extends through openings 96 in the rod 14 into a circular groove 98 in the base 28.

A heat transfer plug 100 (FIG. 1) is positioned within and threaded into the bore of rod 14. The heat transfer plug is provided with a coating of flash powder and an expulsion charge 104 is packed internally of the rod 14 between the plug 100 and the top end of the rod 14.

As shown in FIG. 1, a metal washer 106 and a rubber Washer 108 are positioned on the top end of rod 14. A round nut 110 is threaded to the rod 14 and a metal cover cap 112 frictionally engages the outside surface of the nut and bears against the washer 108.

A parachute 114 (FIG. 1) is housed in a split can container 116 secured by screws 118 to a metal disc 120 which is threaded to the nut 18. A steel plate 122 and a felt disc 124 are positioned in the container 116 to protect the parachute 114 from burning by the expulsion charge 184. The parachute shrouds 126 are attached to a steel loop 128 which is anchored to the disc 120 In operation, the explosive noisemaker device 10/ is loaded into a submarines signal tube (not shown), the key projecting portion 65 of the tripping lever 64 being placed in a key-way provided in the signal tube wall. The safety pin 76 and shaft 78 are then removed. As the device 10 is ejected out of the signal tube by a suitable ejection means (not shown), the projection 65 engages the end of the key-Way and swings the lever 64 on its pivot 66 to release the hammer 70 thus permitting the hammer to strike the initial primer 98 (FIG. 5). The primer ignites the relay fuse 9'4 and a flash from the coating on the heat transfer plug 106} ignites the expulsion charge 104. The expulsion charge forces the cap 112 from the nut 116 and the split can container 116 is forced free from the disc 12% by a shearing action of the screws 118. The split can 116 then falls away and the exposed parachute 114 supports the explosive noisemaker and retards the rate of descent of the noisemaker.

The parachute 114 opens and supports the device 10 before the relay fuse 4 sets off the first delay fuse 56. The fuse 94 burns through the openings 96 in the rod 14,. around the circular groove 98 and through the first orifice 61 in transfer plate 46 to the first fuse 56. As the fuse 56 burns around the groove 54 the relay fuses 58 are ignited in succession and the explosive caps 5i) set off seriatim. The openings 60' provide a continuous train between the fuses 56. It is apparent that as the fuse 56 burns around the groove 54 and through the openings 60, the fuses 56 in the grooves 54 are ignited one after another and the explosive caps 55} are set off successively at a predetermined rate. It is obvious that certain caps of a disc 12 will be set off concurrently with certain of the'caps of a preceding disc by virtue of the simultaneous ignition of the caps through the fuse train described.

The invention described herein may be manufactured and used by or for the Government of the UnitedStates of America for governmental purposes without the payment of any royalties thereon or therefor.

Having described the invention, what is claimed-as novel and desiredto be protected by Letters Patent of the United States is:

1. An underwater soundgenerator comprising a series of discs stacked one upon theother, each disc having'a series of spaced openings, an explosive charge in each of said openings, an annular groove in each disc interconnecting said openings and having an opening leading therefrom intercommunicating with the annular groovev ofthe-next adjacent disc, fuse means in said openings and grooves, means for retaining said .discs in stacked formation with said lead openings in uniform or differentrelative positions with respect to each other and means for initiating the ignition of thefuse associated withthe first disc of the series.

2. A sound generator comprising a series of discs in stacked arrangement, each disc havinga pluralityof apertures for receiving explosive charges, each of said discs being provided with a groove having intercommunicating channels with each of said apertures, and each disc having a singular orifice therein communicating Withthe groove of the next adjacent disc in uniform or different relative positions with respect to each other, and adjustable means for retaining said discs withtheirorifices in adjusted position.

3. A sound generator comprising, a series of discs in stacked arrangement, each disc having a plurality of aperture for receiving exposive charges, each of said discs being provided with a groove having intercommunicating channels with each of said apertures, each disc having a single orifice therein for communicating with the groove of the next adjacent disc in uniform or different relative positions with respect to each other, means for retaining said discs with the single orifices thereof in an adjusted position, each .of said discs having a central opening, said central openings being aligned for receiving an explosive charge therein.

4. Apparatus as in claim 3 including means for retarding the descent of said generator in water, said retarding means being retained adjacent said sound generator, at least a portion of said explosive charge within said central opening being in proximity to said retarding means and operative to release said retarding means upon detonation thereof. 5. Apparatus as in claim 4 including a heat transfer plug inserted within said central opening for detonating said portion of said explosive charge in proximity with said retarding means prior to the detonation of said explosive charges in said apertures in said discs.

6. Apparatus as in claim 5 wherein said retarding means is disposed at one end of said sound generator, a lever and movable hammer are disposed at the other end of 'said sound generator, tripping of said lever causing release of said hammer, and a priming charge is located at said other end within said central opening in the path of travel of said movable hammer.

7. Apparatus as in claim 6 wherein said retarding means comprises a parachute, a split can containing said parachute and attached at said one end of said sound generator, said portion of explosive charge in proximity to said split can upon detonation thereof forcing said split can from said sound generator and expelling said parachute.

References Cited in the file of this patent UNITED STATES PATENTS 372,753 Hurst Nov. 8, 1887 1,300,333 Berry Apr. 15, 1919 1,434,784 Lucas Nov. 7, 1922 FOREIGN PATENTS 498,255 France Oct. 11, 1919 

1. AN UNDERWATER SOUND GENERATOR COMPRISING A SERIES OF DISCS STACKED ONE UPON THE OTHER, EACH DISC HAVING A SERIES OF SPACED OPENINGS, AN EXPLOSIVE CHARGE IN EACH OF SAID OPENINGS, AN ANNULAR GROOVE IN EACH DISC INTERCONNECTING SAID OPENINGS AND HAVING AN OPENING LEADING THEREFROM INTERCOMMUNICATING WITH THE ANNULAR GROOVE OF THE NEXT ADJACENT DISC, FUSE MEANS IN SAID OPENINGS AND GROOVES, MEANS FOR RETAINING SAID DISCS IN STACKED FORMATION WITH SAID LEAD OPENINGS IN UNIFORM OR DIFFERENT RELATIVE POSITIONS WITH RESPECT TO EACH OTHER AND MEANS FOR INITIATING THE IGNITION OF THE FUSE ASSOCIATED WITH THE FIRST DISC OF THE SERIES. 